Pyridin-2-ylmethylsulfinyl-lH-benzimidazoles, as disclosed, for example, in EP-A 0005129, EP-A 0166287 and EP-A 0268956 are becoming increasingly important, because of their H.sup.+ /K.sup.+ ATPase-inhibiting action, for the therapy of diseases which originate from increased gastric acid secretion. Examples of active ingredients which are already commercially available from this group are omeprazole (INN), lansoprazole (INN) and pantoprazole (INN). These active ingredients are also called irreversible proton pump inhibitors.
Control of the microbe, Helicobacter pylori, which is thought to be responsible for certain gastric disorders, by combined use of an antimicrobially-active ingredient which is active against Helicobacter pylori and of an agent which reduces gastric acid has been regarded as the method of choice for some time.
EP-A 0519365 proposes (for the active ingredient pantoprazole) a formulation based on the principle of an alkaline core coated with a water-soluble intermediate layer and with an enteric layer, where improved stability is achieved by using polyvinylpyrrolidone and/or hydroxypropylmethylcellulose as binder for the alkaline core.
EP-A 0342522 discloses a formulation for acid-sensitive benzimidazoles, in which an intermediate layer is located between the alkaline core and the enteric coating and is composed of a film-forming material which has only low solubility in water, such as ethylcellulose and polyvinyl acetate, and of a fine-particle inorganic or organic material which is suspended therein and has low solubility in water, such as magnesium oxide, silicon oxide or sucrose fatty acid esters.
JP-A 59020219 discloses an enteric composition for acid-labile active ingredients which comprises (under the enteric coating) an intermediate layer of a film-forming material, such as hydroxypropylmethylcellulose, hydroxypropylcellulose and hydroxypropylmethylcellulose phthalate with a content of higher fatty acids.
DE-A 3233764 proposes for enteric compositions an intermediate layer which is formed from a water-soluble cellulose ether and a water-soluble mono- or polybasic organic acid, such as citric acid, tartaric acid, and the like.
Combined use of irreversible proton pump inhibitors with antimicrobially-active ingredients does indeed show a good effect against Helicobacter in vitro. However, the clinical effect achieved with this combined use is disappointing. Of practical inconvenience is the great delay in the onset of action.